Monitoring of Diaphorina citri populations from Florida reveals reduced susceptibility to cyantraniliprole and thiamethoxam

The Asian citrus psyllid, <i>Diaphorina citri</i>,<b> </b>is an important insect pest that transmits the causal pathogens of huanglongbing (HLB) in citrus. In Florida, HLB threatens citrus production and insecticide overuse for the vector has resulted in evolution of resistance among populations of <i>D. citri</i> to commonly used insecticides. Cyantraniliprole is effective against nymphal and adult <i>D. citri</i>.<i> </i>However, since the introduction of cyantraniliprole use in Florida, observations have suggested that duration of population suppression following foliar sprays against <i>D. citri </i>has decreased from 60 to 28 d during the period between 2012 and 2020. Here, we sampled populations of <i>D. citri</i> from four locations in FL and measured their susceptibility to cyantraniliprole as compared with a laboratory susceptible culture. A bottle bioassay method was used to measure direct toxicity of insecticides to <i>D. citri</i>. Our results indicate that sufficient field variation exists in susceptibility to cyantraniliprole among populations of <i>D. citri</i> to justify careful management of this insecticide for prevention of insecticide resistance development. <br>